August 2, 2013. The results of a meta-analysis published on July 24, 2013 in BioMed Central Public Health reveal a lower risk of dying over 6 to 13.5 years of follow-up among men and women with higher vitamin D levels.

Lynne Rush of the National Health Service of Greater Glasgow and Clyde and her associates analyzed the findings of nine studies which provided data on serum 25-hydroxyvitamin D status and mortality for a total of 24,297 adults of varying ages. Over the studies’ follow-up periods, 5,324 deaths occurred. After adjusting for several factors, a 19% higher risk of dying from any cause over follow-up was found among those with lower serum vitamin D as compared to higher levels. When the subjects were analyzed according to age, the adjusted risk of dying was 12% higher for subjects with low vitamin D in studies of subjects whose age averaged less than 65 years, and 25% higher for studies whose participants had an average age of over 65 years.

“As far as we are aware, this is the only systematic review and meta-analysis that has specifically investigated whether the apparent association between low vitamin D status and all-cause mortality is age-dependent,” the authors announce. “Although a significant increase in all-cause mortality was found in study participants of all ages with low compared to higher 25-hydroxyvitamin D levels, the pooled effect size was lower for studies with participants with an average age of less than 65 years compared to the studies containing older participants.”

“Further studies investigating the association between vitamin D deficiency and all-cause mortality in younger adults with adjustment for all important confounders (or using randomised trials of supplementation) are required to clarify this relationship,” they conclude.